Authentication

This layer handles user identity, account registration, session lifecycle, and route authorization in web apps. Before you write code, decide whether to use a managed identity service with prebuilt UI flows, or an open-source library that stores user records in your main application database. Managed providers like Clerk supply ready-made components and multi-session security, while libraries give you full control of the schema without per-user subscription fees. A common mistake is building your own password hashing, token rotation, and credential reset flows. That takes time away from the product and adds subtle security vulnerabilities.